Undressing the shear mode of graphite with magnetic field
Mardi 2 mai 2017 14:30
- Duree : 1 heure
Lieu : LNCMI, salle de conférences "René Pauthenet" (bâtiment J, 2ème étage) - 25 rue des martyrs - 38000 Grenoble
Orateur : Clément FAUGERAS (LNCMI)
Layered materials host rigid layer phonon modes describing the shear and breath mode of the multilayer structure. These modes, at relatively low energy (10-50 cm-1), can be investigated with Raman scattering spectroscopy. The shear mode of graphitic materials has a very particular and asymmetric line shape, called the Breit-Wigner-Fano line shape, and which results from quantum interferences when a discrete excited state (the phonon excitation) and a continuum of excitations, are coupled, and are two competiting pathways from a ground state. In this work, based on the evolution of the lineshape with temperature, we identify the electronic continuum responsible for the Fano effect as the continuum of electronic excitations along the H-K-H corners of the graphite Brillouin zone. Finally, by applying a magnetc field, we transform the density of states of the electronic continuum which is condensed due to Landau quantization, and we enhance the Fano factor describing the interaction which finally vanishes for high values of magnetic field, when the excitation spectrum becomes completely discrete.
Contact : anne-laure.barra@lncmi.cnrs.fr
Discipline évènement : (Physique)
Entité organisatrice : (LNCMI)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire LNCMI)
Site de l'évènement : Polygone scientifique
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